Method and apparatus for transmitting time alignment timer report in wireless communication system

ABSTRACT

The present invention relates to a method of transmitting a Time Alignment Timer (TAT) status report by a user equipment (UE) in a wireless communication system. Especially, the method includes the steps of configuring one or more Timing Advance Groups (TAGs); receiving a Timing Advance Command (TAC) for one of the one or more TAGs; starting a TAT for the one TAG; triggering the TAT status report when a remaining time of the TAT for the one TAG is less than a threshold for the one TAG; and transmitting the TAT status report to a network, wherein the TAT status report includes a first type indication indicating that the remaining time of the TAT for the one TAG is less than the threshold.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a National Stage application under 35 U.S.C. § 371of International Application No. PCT/KR2021/008399, filed on Jul. 2,2021, which claims the benefit of Korean Patent Application No.10-2020-0094348, filed on Jul. 29, 2020. The disclosure of the priorapplications are incorporated by reference in their entirety.

TECHNICAL FIELD

The present disclosure relates to a wireless communication system, andmore particularly, to a method for transmitting a Time Alignment Timer(TAT) status report in a wireless communication system and an apparatustherefor.

BACKGROUND

Introduction of new radio communication technologies has led toincreases in the number of user equipments (UEs) to which a base station(BS) provides services in a prescribed resource region, and has also ledto increases in the amount of data and control information that the BStransmits to the UEs. Due to typically limited resources available tothe BS for communication with the UE(s), new techniques are needed bywhich the BS utilizes the limited radio resources to efficientlyreceive/transmit uplink/downlink data and/or uplink/downlink controlinformation. In particular, overcoming delay or latency has become animportant challenge in applications whose performance critically dependson delay/latency

SUMMARY

An object of the present disclosure is to provide a method fortransmitting a Time Alignment Timer (TAT) status report in a wirelesscommunication system and an apparatus therefor.

The object of the present disclosure can be achieved by the method fortransmitting a Time Alignment Timer (TAT) status report by a userequipment (UE) in a wireless communication system, comprising the stepsof configuring one or more Timing Advance Groups (TAGs); receiving aTiming Advance Command (TAC) for one of the one or more TAGs; starting aTAT for the one TAG; triggering the TAT status report when a remainingtime of the TAT for the one TAG is less than a threshold for the oneTAG; and transmitting the TAT status report to a network, wherein theTAT status report includes a first type indication indicating that theremaining time of the TAT for the one TAG is less than the threshold.

Further, it is suggested a user equipment (UE) in a wirelesscommunication system, the UE comprising: at least one transceiver; atleast one processor; and at least one computer memory operablyconnectable to the at least one processor and storing instructions that,when executed, cause the at least one processor to perform operationscomprising: configuring one or more Timing Advance Groups (TAGs);receiving a Timing Advance Command (TAC) for one of the one or moreTAGs; starting a Time Alignment Timer (TAT) for the one TAG; triggeringthe TAT status report when a remaining time of the TAT for the one TAGis less than a threshold for the one TAG; and transmitting the TATstatus report to a network, wherein the TAT status report includes afirst type indication indicating that the remaining time of the TAT forthe one TAG is less than the threshold.

Preferably, if a number of configured TAGs is greater than 2, the TATstatus report further includes first type indications indicating whetherthe remaining time of the TAT for the one or more TAGs other than theone TAG is less than the threshold or not.

Preferably, the TAT status report further includes second typeindications for the one or more TAGs indicating whether the UE wants tokeep the TAT running or not.

Preferably, the UE further receives information about one or morethresholds for the one or more TAGs from the network.

Preferably, after transmitting the TAT status report, the network maytransmit a TAC for the one TAG. Then, the UE may restart the TAT for theone TAG.

According to the aforementioned embodiments of the present disclosure,the UE can inform the remaining time of TAT and its preference to keepthe TAT running. Based on the information, the network can transmit TACto restart the TAT in the UE. Therefore, the UE can avoid release of ULresource due to TAT expiry when the UE wants to perform UL transmissionin a near future. This would help to reduce the delay in ULtransmission.

Effects obtainable from the present disclosure may be non-limited by theabove mentioned effect. And, other unmentioned effects can be clearlyunderstood from the following description by those having ordinary skillin the technical field to which the present disclosure pertains.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the disclosure, illustrate embodiments of thedisclosure and together with the description serve to explain theprinciple of the disclosure:

FIG. 1 illustrates an example of a communication system 1 to whichimplementations of the present disclosure is applied;

FIG. 2 is a block diagram illustrating examples of communication deviceswhich can perform a method according to the present disclosure;

FIG. 3 illustrates another example of a wireless device which canperform implementations of the present disclosure;

FIGS. 4A and 4B illustrate examples of protocol stacks in a thirdgeneration partnership project (3GPP) based wireless communicationsystem;

FIG. 5 illustrates an example of a frame structure in a 3GPP basedwireless communication system;

FIG. 6 illustrates a data flow example in the 3GPP new radio (NR)system;

FIGS. 7A and 7B illustrate examples of PDSCH time domain resourceallocation by PDCCH, and an example of PUSCH time resource allocation byPDCCH;

FIG. 8 illustrates an example of physical layer processing at atransmitting side;

FIG. 9 illustrates an example of physical layer processing at areceiving side.

FIG. 10 illustrates operations of the wireless devices based on theimplementations of the present disclosure;

FIG. 11 shows an example of Timing Advance Command MAC CE in the NRsystem;

FIG. 12 shows an example of Absolute Timing Advance Command MAC CE inthe NR system;

FIG. 13 shows an example of TAT status report for one TAG according tothe present disclosure;

FIG. 14 shows an example of TAT status report for all TAGs according tothe present disclosure;

FIG. 15 shows another example of TAT status report for all TAGsaccording to the present disclosure; and

FIG. 16 shows a procedure for transmitting a TAT status report accordingto the present disclosure.

DETAILED DESCRIPTION

Reference will now be made in detail to the exemplary implementations ofthe present disclosure, examples of which are illustrated in theaccompanying drawings. The detailed description, which will be givenbelow with reference to the accompanying drawings, is intended toexplain exemplary implementations of the present disclosure, rather thanto show the only implementations that can be implemented according tothe disclosure. The following detailed description includes specificdetails in order to provide a thorough understanding of the presentdisclosure. However, it will be apparent to those skilled in the artthat the present disclosure may be practiced without such specificdetails.

The following techniques, apparatuses, and systems may be applied to avariety of wireless multiple access systems. Examples of the multipleaccess systems include a code division multiple access (CDMA) system, afrequency division multiple access (FDMA) system, a time divisionmultiple access (TDMA) system, an orthogonal frequency division multipleaccess (OFDMA) system, a single carrier frequency division multipleaccess (SC-FDMA) system, and a multicarrier frequency division multipleaccess (MC-FDMA) system. CDMA may be embodied through radio technologysuch as universal terrestrial radio access (UTRA) or CDMA2000. TDMA maybe embodied through radio technology such as global system for mobilecommunications (GSM), general packet radio service (GPRS), or enhanceddata rates for GSM evolution (EDGE). OFDMA may be embodied through radiotechnology such as institute of electrical and electronics engineers(IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, or evolved UTRA(E-UTRA). UTRA is a part of a universal mobile telecommunications system(UMTS). 3rd generation partnership project (3GPP) long term evolution(LTE) is a part of evolved UMTS (E-UMTS) using E-UTRA. 3GPP LTE employsOFDMA in DL and SC-FDMA in UL. LTE-advanced (LTE-A) is an evolvedversion of 3GPP LTE.

For convenience of description, implementations of the presentdisclosure are mainly described in regards to a 3GPP based wirelesscommunication system. However, the technical features of the presentdisclosure are not limited thereto. For example, although the followingdetailed description is given based on a mobile communication systemcorresponding to a 3GPP based wireless communication system, aspects ofthe present disclosure that are not limited to 3GPP based wirelesscommunication system are applicable to other mobile communicationsystems. For terms and technologies which are not specifically describedamong the terms of and technologies employed in the present disclosure,the wireless communication standard documents published before thepresent disclosure may be referenced. For example, the followingdocuments may be referenced.

3GPP LTE

-   -   3GPP TS 36.211: Physical channels and modulation    -   3GPP TS 36.212: Multiplexing and channel coding    -   3GPP TS 36.213: Physical layer procedures    -   3GPP TS 36.214: Physical layer; Measurements    -   3GPP TS 36.300: Overall description    -   3GPP TS 36.304: User Equipment (UE) procedures in idle mode    -   3GPP TS 36.314: Layer 2—Measurements    -   3GPP TS 36.321: Medium Access Control (MAC) protocol    -   3GPP TS 36.322: Radio Link Control (RLC) protocol    -   3GPP TS 36.323: Packet Data Convergence Protocol (PDCP)    -   3GPP TS 36.331: Radio Resource Control (RRC) protocol

3GPP NR (e.g. 5G)

-   -   3GPP TS 38.211: Physical channels and modulation    -   3GPP TS 38.212: Multiplexing and channel coding    -   3GPP TS 38.213: Physical layer procedures for control    -   3GPP TS 38.214: Physical layer procedures for data    -   3GPP TS 38.215: Physical layer measurements    -   3GPP TS 38.300: Overall description    -   3GPP TS 38.304: User Equipment (UE) procedures in idle mode and        in RRC inactive state    -   3GPP TS 38.321: Medium Access Control (MAC) protocol    -   3GPP TS 38.322: Radio Link Control (RLC) protocol    -   3GPP TS 38.323: Packet Data Convergence Protocol (PDCP)    -   3GPP TS 38.331: Radio Resource Control (RRC) protocol    -   3GPP TS 37.324: Service Data Adaptation Protocol (SDAP)    -   3GPP TS 37.340: Multi-connectivity; Overall description

In the present disclosure, a user equipment (UE) may be a fixed ormobile device. Examples of the UE include various devices that transmitand receive user data and/or various kinds of control information to andfrom a base station (BS). In the present disclosure, a BS generallyrefers to a fixed station that performs communication with a UE and/oranother BS, and exchanges various kinds of data and control informationwith the UE and another BS. The BS may be referred to as an advancedbase station (ABS), a node-B (NB), an evolved node-B (eNB), a basetransceiver system (BTS), an access point (AP), a processing server(PS), etc. Especially, a BS of the UMTS is referred to as a NB, a BS ofthe enhanced packet core (EPC)/long term evolution (LTE) system isreferred to as an eNB, and a BS of the new radio (NR) system is referredto as a gNB.

In the present disclosure, a node refers to a point capable oftransmitting/receiving a radio signal through communication with a UE.Various types of BSs may be used as nodes irrespective of the termsthereof. For example, a BS, a node B (NB), an e-node B (eNB), apico-cell eNB (PeNB), a home eNB (HeNB), a relay, a repeater, etc. maybe a node. In addition, the node may not be a BS. For example, the nodemay be a radio remote head (RRH) or a radio remote unit (RRU). The RRHor RRU generally has a lower power level than a power level of a BS.Since the RRH or RRU (hereinafter, RRH/RRU) is generally connected tothe BS through a dedicated line such as an optical cable, cooperativecommunication between RRH/RRU and the BS can be smoothly performed incomparison with cooperative communication between BSs connected by aradio line. At least one antenna is installed per node. The antenna mayinclude a physical antenna or an antenna port or a virtual antenna.

In the present disclosure, the term “cell” may refer to a geographicarea to which one or more nodes provide a communication system, or referto radio resources. A “cell” of a geographic area may be understood ascoverage within which a node can provide service using a carrier and a“cell” as radio resources (e.g. time-frequency resources) is associatedwith bandwidth (BW) which is a frequency range configured by thecarrier. The “cell” associated with the radio resources is defined by acombination of downlink resources and uplink resources, for example, acombination of a downlink (DL) component carrier (CC) and an uplink (UL)CC. The cell may be configured by downlink resources only, or may beconfigured by downlink resources and uplink resources. Since DLcoverage, which is a range within which the node is capable oftransmitting a valid signal, and UL coverage, which is a range withinwhich the node is capable of receiving the valid signal from the UE,depends upon a carrier carrying the signal, the coverage of the node maybe associated with coverage of the “cell” of radio resources used by thenode. Accordingly, the term “cell” may be used to represent servicecoverage of the node sometimes, radio resources at other times, or arange that signals using the radio resources can reach with validstrength at other times.

In the present disclosure, a physical downlink control channel (PDCCH),and a physical downlink shared channel (PDSCH) refer to a set oftime-frequency resources or resource elements (REs) carrying downlinkcontrol information (DCI), and a set of time-frequency resources or REscarrying downlink data, respectively. In addition, a physical uplinkcontrol channel (PUCCH), a physical uplink shared channel (PUSCH) and aphysical random access channel (PRACH) refer to a set of time-frequencyresources or REs carrying uplink control information (UCI), a set oftime-frequency resources or REs carrying uplink data and a set oftime-frequency resources or REs carrying random access signals,respectively.

In carrier aggregation (CA), two or more CCs are aggregated. A UE maysimultaneously receive or transmit on one or multiple CCs depending onits capabilities. CA is supported for both contiguous and non-contiguousCCs. When CA is configured the UE only has one radio resource control(RRC) connection with the network. At RRC connectionestablishment/re-establishment/handover, one serving cell provides thenon-access stratum (NAS) mobility information, and at RRC connectionre-establishment/handover, one serving cell provides the security input.This cell is referred to as the Primary Cell (PCell). The PCell is acell, operating on the primary frequency, in which the UE eitherperforms the initial connection establishment procedure or initiates theconnection re-establishment procedure. Depending on UE capabilities,Secondary Cells (SCells) can be configured to form together with thePCell a set of serving cells. An SCell is a cell providing additionalradio resources on top of Special Cell. The configured set of servingcells for a UE therefore always consists of one PCell and one or moreSCells. In the present disclosure, for dual connectivity (DC) operation,the term “special Cell” refers to the PCell of the master cell group(MCG) or the PSCell of the secondary cell group (SCG), and otherwise theterm Special Cell refers to the PCell. An SpCell supports physicaluplink control channel (PUCCH) transmission and contention-based randomaccess, and is always activated. The MCG is a group of serving cellsassociated with a master node, comprising of the SpCell (PCell) andoptionally one or more SCells. The SCG is the subset of serving cellsassociated with a secondary node, comprising of the PSCell and zero ormore SCells, for a UE configured with DC. For a UE in RRC_CONNECTED notconfigured with CA/DC there is only one serving cell comprising of thePCell. For a UE in RRC_CONNECTED configured with CA/DC the term “servingcells” is used to denote the set of cells comprising of the SpCell(s)and all SCells.

The MCG is a group of serving cells associated with a master BS whichterminates at least S1-MME, and the SCG is a group of serving cellsassociated with a secondary BS that is providing additional radioresources for the UE but is not the master BS. The SCG includes aprimary SCell (PSCell) and optionally one or more SCells. In DC, two MACentities are configured in the UE: one for the MCG and one for the SCG.Each MAC entity is configured by RRC with a serving cell supportingPUCCH transmission and contention based Random Access. In the presentdisclosure, the term SpCell refers to such cell, whereas the term SCellrefers to other serving cells. The term SpCell either refers to thePCell of the MCG or the PSCell of the SCG depending on if the MAC entityis associated to the MCG or the SCG, respectively.

In the present disclosure, monitoring a channel refers to attempting todecode the channel. For example, monitoring a physical downlink controlchannel (PDCCH) refers to attempting to decode PDCCH(s) (or PDCCHcandidates).

In the present disclosure, “C-RNTI” refers to a cell RNTI, “SI-RNTI”refers to a system information RNTI, “P-RNTI” refers to a paging RNTI,“RA-RNTI” refers to a random access RNTI, “SC-RNTI” refers to a singlecell RNTI″, “SL-RNTI” refers to a sidelink RNTI, “SPS C-RNTI” refers toa semi-persistent scheduling C-RNTI, and “CS-RNTI” refers to aconfigured scheduling RNTI.

FIG. 1 illustrates an example of a communication system 1 to whichimplementations of the present disclosure is applied.

Three main requirement categories for 5G include (1) a category ofenhanced mobile broadband (eMBB), (2) a category of massive machine typecommunication (mMTC), and (3) a category of ultra-reliable and lowlatency communications (URLLC).

Partial use cases may require a plurality of categories for optimizationand other use cases may focus only upon one key performance indicator(KPI). 5G supports such various use cases using a flexible and reliablemethod.

eMBB far surpasses basic mobile Internet access and covers abundantbidirectional work and media and entertainment applications in cloud andaugmented reality. Data is one of 5G core motive forces and, in a 5Gera, a dedicated voice service may not be provided for the first time.In 5G, it is expected that voice will be simply processed as anapplication program using data connection provided by a communicationsystem. Main causes for increased traffic volume are due to an increasein the size of content and an increase in the number of applicationsrequiring high data transmission rate. A streaming service (of audio andvideo), conversational video, and mobile Internet access will be morewidely used as more devices are connected to the Internet. These manyapplication programs require connectivity of an always turned-on statein order to push real-time information and alarm for users. Cloudstorage and applications are rapidly increasing in a mobilecommunication platform and may be applied to both work andentertainment. The cloud storage is a special use case which acceleratesgrowth of uplink data transmission rate. 5G is also used for remote workof cloud. When a tactile interface is used, 5G demands much lowerend-to-end latency to maintain user good experience. Entertainment, forexample, cloud gaming and video streaming, is another core element whichincreases demand for mobile broadband capability. Entertainment isessential for a smartphone and a tablet in any place including highmobility environments such as a train, a vehicle, and an airplane. Otheruse cases are augmented reality for entertainment and informationsearch. In this case, the augmented reality requires very low latencyand instantaneous data volume.

In addition, one of the most expected 5G use cases relates a functioncapable of smoothly connecting embedded sensors in all fields, i.e.,mMTC. It is expected that the number of potential IoT devices will reach204 hundred million up to the year of 2020. An industrial IoT is one ofcategories of performing a main role enabling a smart city, assettracking, smart utility, agriculture, and security infrastructurethrough 5G.

URLLC includes a new service that will change industry through remotecontrol of main infrastructure and an ultra-reliable/availablelow-latency link such as a self-driving vehicle. A level of reliabilityand latency is essential to control a smart grid, automatize industry,achieve robotics, and control and adjust a drone.

5G is a means of providing streaming evaluated as a few hundred megabitsper second to gigabits per second and may complement fiber-to-the-home(FTTH) and cable-based broadband (or DOCSIS). Such fast speed is neededto deliver TV in resolution of 4K or more (6K, 8K, and more), as well asvirtual reality and augmented reality. Virtual reality (VR) andaugmented reality (AR) applications include almost immersive sportsgames. A specific application program may require a special networkconfiguration. For example, for VR games, gaming companies need toincorporate a core server into an edge network server of a networkoperator in order to minimize latency.

Automotive is expected to be a new important motivated force in 5Gtogether with many use cases for mobile communication for vehicles. Forexample, entertainment for passengers requires high simultaneouscapacity and mobile broadband with high mobility. This is because futureusers continue to expect connection of high quality regardless of theirlocations and speeds. Another use case of an automotive field is an ARdashboard. The AR dashboard causes a driver to identify an object in thedark in addition to an object seen from a front window and displays adistance from the object and a movement of the object by overlappinginformation talking to the driver. In the future, a wireless moduleenables communication between vehicles, information exchange between avehicle and supporting infrastructure, and information exchange betweena vehicle and other connected devices (e.g., devices accompanied by apedestrian). A safety system guides alternative courses of a behavior sothat a driver may drive more safely drive, thereby lowering the dangerof an accident. The next stage will be a remotely controlled orself-driven vehicle. This requires very high reliability and very fastcommunication between different self-driven vehicles and between avehicle and infrastructure. In the future, a self-driven vehicle willperform all driving activities and a driver will focus only uponabnormal traffic that the vehicle cannot identify. Technicalrequirements of a self-driven vehicle demand ultra-low latency andultra-high reliability so that traffic safety is increased to a levelthat cannot be achieved by human being.

A smart city and a smart home/building mentioned as a smart society willbe embedded in a high-density wireless sensor network. A distributednetwork of an intelligent sensor will identify conditions for costs andenergy-efficient maintenance of a city or a home. Similar configurationsmay be performed for respective households. All of temperature sensors,window and heating controllers, burglar alarms, and home appliances arewirelessly connected. Many of these sensors are typically low in datatransmission rate, power, and cost. However, real-time HD video may bedemanded by a specific type of device to perform monitoring.

Consumption and distribution of energy including heat or gas isdistributed at a higher level so that automated control of thedistribution sensor network is demanded. The smart grid collectsinformation and connects the sensors to each other using digitalinformation and communication technology so as to act according to thecollected information. Since this information may include behaviors of asupply company and a consumer, the smart grid may improve distributionof fuels such as electricity by a method having efficiency, reliability,economic feasibility, production sustainability, and automation. Thesmart grid may also be regarded as another sensor network having lowlatency.

Mission critical application (e.g. e-health) is one of 5G use scenarios.A health part contains many application programs capable of enjoyingbenefit of mobile communication. A communication system may supportremote treatment that provides clinical treatment in a faraway place.Remote treatment may aid in reducing a barrier against distance andimprove access to medical services that cannot be continuously availablein a faraway rural area. Remote treatment is also used to performimportant treatment and save lives in an emergency situation. Thewireless sensor network based on mobile communication may provide remotemonitoring and sensors for parameters such as heart rate and bloodpressure.

Wireless and mobile communication gradually becomes important in thefield of an industrial application. Wiring is high in installation andmaintenance cost. Therefore, a possibility of replacing a cable withreconstructible wireless links is an attractive opportunity in manyindustrial fields. However, in order to achieve this replacement, it isnecessary for wireless connection to be established with latency,reliability, and capacity similar to those of the cable and managementof wireless connection needs to be simplified. Low latency and a verylow error probability are new requirements when connection to 5G isneeded.

Logistics and freight tracking are important use cases for mobilecommunication that enables inventory and package tracking anywhere usinga location-based information system. The use cases of logistics andfreight typically demand low data rate but require location informationwith a wide range and reliability.

Referring to FIG. 1 , the communication system 1 includes wirelessdevices, base stations (BSs), and a network. Although FIG. 1 illustratesa 5G network as an example of the network of the communication system 1,the implementations of the present disclosure are not limited to the 5Gsystem, and can be applied to the future communication system beyond the5G system.

The BSs and the network may be implemented as wireless devices and aspecific wireless device 200 a may operate as a BS/network node withrespect to other wireless devices.

The wireless devices represent devices performing communication usingradio access technology (RAT) (e.g., 5G New RAT (NR)) or Long-TermEvolution (LTE)) and may be referred to as communication/radio/5Gdevices. The wireless devices may include, without being limited to, arobot 100 a, vehicles 100 b-1 and 100 b-2, an eXtended Reality (XR)device 100 c, a hand-held device 100 d, a home appliance 100 e, anInternet of Things (IoT) device 100 f, and an Artificial Intelligence(AI) device/server 400. For example, the vehicles may include a vehiclehaving a wireless communication function, an autonomous driving vehicle,and a vehicle capable of performing communication between vehicles. Thevehicles may include an Unmanned Aerial Vehicle (UAV) (e.g., a drone).The XR device may include an Augmented Reality (AR)/Virtual Reality(VR)/Mixed Reality (MR) device and may be implemented in the form of aHead-Mounted Device (HMD), a Head-Up Display (HUD) mounted in a vehicle,a television, a smartphone, a computer, a wearable device, a homeappliance device, a digital signage, a vehicle, a robot, etc. Thehand-held device may include a smartphone, a smartpad, a wearable device(e.g., a smartwatch or a smartglasses), and a computer (e.g., anotebook). The home appliance may include a TV, a refrigerator, and awashing machine. The IoT device may include a sensor and a smartmeter.

In the present disclosure, the wireless devices 100 a to 100 f may becalled user equipments (UEs). A user equipment (UE) may include, forexample, a cellular phone, a smartphone, a laptop computer, a digitalbroadcast terminal, a personal digital assistant (PDA), a portablemultimedia player (PMP), a navigation system, a slate personal computer(PC), a tablet PC, an ultrabook, a vehicle, a vehicle having anautonomous traveling function, a connected car, an unmanned aerialvehicle (UAV), an artificial intelligence (AI) module, a robot, anaugmented reality (AR) device, a virtual reality (VR) device, a mixedreality (MR) device, a hologram device, a public safety device, an MTCdevice, an IoT device, a medical device, a FinTech device (or afinancial device), a security device, a weather/environment device, adevice related to a 5G service, or a device related to a fourthindustrial revolution field. The unmanned aerial vehicle (UAV) may be,for example, an aircraft aviated by a wireless control signal without ahuman being onboard. The VR device may include, for example, a devicefor implementing an object or a background of the virtual world. The ARdevice may include, for example, a device implemented by connecting anobject or a background of the virtual world to an object or a backgroundof the real world. The MR device may include, for example, a deviceimplemented by merging an object or a background of the virtual worldinto an object or a background of the real world. The hologram devicemay include, for example, a device for implementing a stereoscopic imageof 360 degrees by recording and reproducing stereoscopic information,using an interference phenomenon of light generated when two laserlights called holography meet. The public safety device may include, forexample, an image relay device or an image device that is wearable onthe body of a user. The MTC device and the IoT device may be, forexample, devices that do not require direct human intervention ormanipulation. For example, the MTC device and the IoT device may includesmartmeters, vending machines, thermometers, smartbulbs, door locks, orvarious sensors. The medical device may be, for example, a device usedfor the purpose of diagnosing, treating, relieving, curing, orpreventing disease. For example, the medical device may be a device usedfor the purpose of diagnosing, treating, relieving, or correcting injuryor impairment. For example, the medical device may be a device used forthe purpose of inspecting, replacing, or modifying a structure or afunction. For example, the medical device may be a device used for thepurpose of adjusting pregnancy. For example, the medical device mayinclude a device for treatment, a device for operation, a device for (invitro) diagnosis, a hearing aid, or a device for procedure. The securitydevice may be, for example, a device installed to prevent a danger thatmay arise and to maintain safety. For example, the security device maybe a camera, a CCTV, a recorder, or a black box. The FinTech device maybe, for example, a device capable of providing a financial service suchas mobile payment. For example, the FinTech device may include a paymentdevice or a point of sales (POS) system. The weather/environment devicemay include, for example, a device for monitoring or predicting aweather/environment.

The wireless devices 100 a to 100 f may be connected to the network 300via the BSs 200. An AI technology may be applied to the wireless devices100 a to 100 f and the wireless devices 100 a to 100 f may be connectedto the AI server 400 via the network 300. The network 300 may beconfigured using a 3G network, a 4G (e.g., LTE) network, a 5G (e.g., NR)network, and a beyond-5G network. Although the wireless devices 100 a to100 f may communicate with each other through the BSs 200/network 300,the wireless devices 100 a to 100 f may perform direct communication(e.g., sidelink communication) with each other without passing throughthe BSs/network. For example, the vehicles 100 b-1 and 100 b-2 mayperform direct communication (e.g. Vehicle-to-Vehicle(V2V)/Vehicle-to-everything (V2X) communication). The IoT device (e.g.,a sensor) may perform direct communication with other IoT devices (e.g.,sensors) or other wireless devices 100 a to 100 f.

Wireless communication/connections 150 a and 150 b may be establishedbetween the wireless devices 100 a to 100 f/BS 200-BS 200. Herein, thewireless communication/connections may be established through variousRATs (e.g., 5G NR) such as uplink/downlink communication 150 a andsidelink communication 150 b (or D2D communication). The wirelessdevices and the BSs/the wireless devices may transmit/receive radiosignals to/from each other through the wirelesscommunication/connections 150 a and 150 b. For example, the wirelesscommunication/connections 150 a and 150 b may transmit/receive signalsthrough various physical channels. To this end, at least a part ofvarious configuration information configuring processes, various signalprocessing processes (e.g., channel encoding/decoding,modulation/demodulation, and resource mapping/demapping), and resourceallocating processes, for transmitting/receiving radio signals, may beperformed based on the various proposals of the present disclosure.

FIG. 2 is a block diagram illustrating examples of communication deviceswhich can perform a method according to the present disclosure.

Referring to FIG. 2 , a first wireless device 100 and a second wirelessdevice 200 may transmit/receive radio signals to/from an external devicethrough a variety of RATs (e.g., LTE and NR). In FIG. 2 , {the firstwireless device 100 and the second wireless device 200} may correspondto {the wireless device 100 a to 100 f and the BS 200} and/or {thewireless device 100 a to 100 f and the wireless device 100 a to 100 f}of FIG. 1 .

The first wireless device 100 may include one or more processors 102 andone or more memories 104 and additionally further include one or moretransceivers 106 and/or one or more antennas 108. The processor(s) 102may control the memory(s) 104 and/or the transceiver(s) 106 and may beconfigured to implement the functions, procedures, and/or methodsdescribed in the present disclosure. For example, the processor(s) 102may process information within the memory(s) 104 to generate firstinformation/signals and then transmit radio signals including the firstinformation/signals through the transceiver(s) 106. The processor(s) 102may receive radio signals including second information/signals throughthe transceiver 106 and then store information obtained by processingthe second information/signals in the memory(s) 104. The memory(s) 104may be connected to the processor(s) 102 and may store a variety ofinformation related to operations of the processor(s) 102. For example,the memory(s) 104 may store software code including commands forperforming a part or the entirety of processes controlled by theprocessor(s) 102 or for performing the procedures and/or methodsdescribed in the present disclosure. Herein, the processor(s) 102 andthe memory(s) 104 may be a part of a communication modem/circuit/chipdesigned to implement RAT (e.g., LTE or NR). The transceiver(s) 106 maybe connected to the processor(s) 102 and transmit and/or receive radiosignals through one or more antennas 108. Each of the transceiver(s) 106may include a transmitter and/or a receiver. The transceiver(s) 106 maybe interchangeably used with radio frequency (RF) unit(s). In thepresent disclosure, the wireless device may represent a communicationmodem/circuit/chip.

The second wireless device 200 may include one or more processors 202and one or more memories 204 and additionally further include one ormore transceivers 206 and/or one or more antennas 208. The processor(s)202 may control the memory(s) 204 and/or the transceiver(s) 206 and maybe configured to implement the functions, procedures, and/or methodsdescribed in the present disclosure. For example, the processor(s) 202may process information within the memory(s) 204 to generate thirdinformation/signals and then transmit radio signals including the thirdinformation/signals through the transceiver(s) 206. The processor(s) 202may receive radio signals including fourth information/signals throughthe transceiver(s) 106 and then store information obtained by processingthe fourth information/signals in the memory(s) 204. The memory(s) 204may be connected to the processor(s) 202 and may store a variety ofinformation related to operations of the processor(s) 202. For example,the memory(s) 204 may store software code including commands forperforming a part or the entirety of processes controlled by theprocessor(s) 202 or for performing the procedures and/or methodsdescribed in the present disclosure. Herein, the processor(s) 202 andthe memory(s) 204 may be a part of a communication modem/circuit/chipdesigned to implement RAT (e.g., LTE or NR). The transceiver(s) 206 maybe connected to the processor(s) 202 and transmit and/or receive radiosignals through one or more antennas 208. Each of the transceiver(s) 206may include a transmitter and/or a receiver. The transceiver(s) 206 maybe interchangeably used with RF unit(s). In the present disclosure, thewireless device may represent a communication modem/circuit/chip.

Hereinafter, hardware elements of the wireless devices 100 and 200 willbe described more specifically. One or more protocol layers may beimplemented by, without being limited to, one or more processors 102 and202. For example, the one or more processors 102 and 202 may implementone or more layers (e.g., functional layers such as PHY, MAC, RLC, PDCP,RRC, and SDAP). The one or more processors 102 and 202 may generate oneor more Protocol Data Units (PDUs) and/or one or more Service Data Unit(SDUs) according to the functions, procedures, proposals, and/or methodsdisclosed in the present disclosure. The one or more processors 102 and202 may generate messages, control information, data, or informationaccording to the functions, procedures, proposals, and/or methodsdisclosed in the present disclosure. The one or more processors 102 and202 may generate signals (e.g., baseband signals) including PDUs, SDUs,messages, control information, data, or information according to thefunctions, procedures, proposals, and/or methods disclosed in thepresent disclosure and provide the generated signals to the one or moretransceivers 106 and 206. The one or more processors 102 and 202 mayreceive the signals (e.g., baseband signals) from the one or moretransceivers 106 and 206 and acquire the PDUs, SDUs, messages, controlinformation, data, or information according to the functions,procedures, proposals, and/or methods disclosed in the presentdisclosure.

The one or more processors 102 and 202 may be referred to ascontrollers, microcontrollers, microprocessors, or microcomputers. Theone or more processors 102 and 202 may be implemented by hardware,firmware, software, or a combination thereof. As an example, one or moreApplication Specific Integrated Circuits (ASICs), one or more DigitalSignal Processors (DSPs), one or more Digital Signal Processing Devices(DSPDs), one or more Programmable Logic Devices (PLDs), or one or moreField Programmable Gate Arrays (FPGAs) may be included in the one ormore processors 102 and 202. The functions, procedures, proposals,and/or methods disclosed in the present disclosure may be implementedusing firmware or software and the firmware or software may beconfigured to include the modules, procedures, or functions. Firmware orsoftware configured to perform the functions, procedures, proposals,and/or methods disclosed in the present disclosure may be included inthe one or more processors 102 and 202 or stored in the one or morememories 104 and 204 so as to be driven by the one or more processors102 and 202. The functions, procedures, proposals, and/or methodsdisclosed in the present disclosure may be implemented using firmware orsoftware in the form of code, commands, and/or a set of commands.

The one or more memories 104 and 204 may be connected to the one or moreprocessors 102 and 202 and store various types of data, signals,messages, information, programs, code, instructions, and/or commands.The one or more memories 104 and 204 may be configured by Read-OnlyMemories (ROMs), Random Access Memories (RAMs), Electrically ErasableProgrammable Read-Only Memories (EPROMs), flash memories, hard drives,registers, cash memories, computer-readable storage media, and/orcombinations thereof. The one or more memories 104 and 204 may belocated at the interior and/or exterior of the one or more processors102 and 202. The one or more memories 104 and 204 may be connected tothe one or more processors 102 and 202 through various technologies suchas wired or wireless connection.

The one or more transceivers 106 and 206 may transmit user data, controlinformation, and/or radio signals/channels, mentioned in the methodsand/or operational flowcharts of the present disclosure, to one or moreother devices. The one or more transceivers 106 and 206 may receive userdata, control information, and/or radio signals/channels, mentioned inthe functions, procedures, proposals, methods, and/or operationalflowcharts disclosed in the present disclosure, from one or more otherdevices. For example, the one or more transceivers 106 and 206 may beconnected to the one or more processors 102 and 202 and transmit andreceive radio signals. For example, the one or more processors 102 and202 may perform control so that the one or more transceivers 106 and 206may transmit user data, control information, or radio signals to one ormore other devices. The one or more processors 102 and 202 may performcontrol so that the one or more transceivers 106 and 206 may receiveuser data, control information, or radio signals from one or more otherdevices. The one or more transceivers 106 and 206 may be connected tothe one or more antennas 108 and 208 and the one or more transceivers106 and 206 may be configured to transmit and receive user data, controlinformation, and/or radio signals/channels, mentioned in the functions,procedures, proposals, methods, and/or operational flowcharts disclosedin the present disclosure, through the one or more antennas 108 and 208.In the present disclosure, the one or more antennas may be a pluralityof physical antennas or a plurality of logical antennas (e.g., antennaports). The one or more transceivers 106 and 206 may convert receivedradio signals/channels etc. from RF band signals into baseband signalsin order to process received user data, control information, radiosignals/channels, etc. using the one or more processors 102 and 202. Theone or more transceivers 106 and 206 may convert the user data, controlinformation, radio signals/channels, etc. processed using the one ormore processors 102 and 202 from the base band signals into the RF bandsignals. To this end, the one or more transceivers 106 and 206 mayinclude (analog) oscillators and/or filters. For example, thetransceivers 106 and 206 can up-convert OFDM baseband signals to acarrier frequency by their (analog) oscillators and/or filters under thecontrol of the processors 102 and 202 and transmit the up-converted OFDMsignals at the carrier frequency. The transceivers 106 and 206 mayreceive OFDM signals at a carrier frequency and down-convert the OFDMsignals into OFDM baseband signals by their (analog) oscillators and/orfilters under the control of the transceivers 102 and 202.

In the implementations of the present disclosure, a UE may operate as atransmitting device in uplink (UL) and as a receiving device in downlink(DL). In the implementations of the present disclosure, a BS may operateas a receiving device in UL and as a transmitting device in DL.Hereinafter, for convenience of description, it is mainly assumed thatthe first wireless device 100 acts as the UE, and the second wirelessdevice 200 acts as the BS, unless otherwise mentioned or described. Forexample, the processor(s) 102 connected to, mounted on or launched inthe first wireless device 100 may be configured to perform the UEbehavior according to an implementation of the present disclosure orcontrol the transceiver(s) 106 to perform the UE behavior according toan implementation of the present disclosure. The processor(s) 202connected to, mounted on or launched in the second wireless device 200may be configured to perform the BS behavior according to animplementation of the present disclosure or control the transceiver(s)206 to perform the BS behavior according to an implementation of thepresent disclosure.

In the present disclosure, at least one memory (e.g. 104 or 204) maystore instructions or programs that, when executed, cause at least oneprocessor, which is operably connected thereto, to perform operationsaccording to some embodiments or implementations of the presentdisclosure.

In the present disclosure, a computer readable storage medium stores atleast one instructions or computer programs that, when executed by atleast one processor, cause the at least one processor to performoperations according to some embodiments or implementations of thepresent disclosure.

In the present disclosure, a processing device or apparatus may compriseat least one processor, and at least one computer memory connectable tothe at least one processor and storing instructions that, when executed,cause the at least one processor to perform operations according to someembodiments or implementations of the present disclosure.

FIG. 3 illustrates another example of a wireless device which canperform implementations of the present disclosure. The wireless devicemay be implemented in various forms according to a use-case/service(refer to FIG. 1 ).

Referring to FIG. 3 , wireless devices 100 and 200 may correspond to thewireless devices 100 and 200 of FIG. 2 and may be configured by variouselements, components, units/portions, and/or modules. For example, eachof the wireless devices 100 and 200 may include a communication unit110, a control unit 120, a memory unit 130, and additional components140. The communication unit may include a communication circuit 112 andtransceiver(s) 114. For example, the communication circuit 112 mayinclude the one or more processors 102 and 202 of FIG. 2 and/or the oneor more memories 104 and 204 of FIG. 2 . For example, the transceiver(s)114 may include the one or more transceivers 106 and 206 of FIG. 2and/or the one or more antennas 108 and 208 of FIG. 2 . The control unit120 is electrically connected to the communication unit 110, the memory130, and the additional components 140 and controls overall operation ofthe wireless devices. For example, the control unit 120 may control anelectric/mechanical operation of the wireless device based onprograms/code/commands/information stored in the memory unit 130. Thecontrol unit 120 may transmit the information stored in the memory unit130 to the exterior (e.g., other communication devices) via thecommunication unit 110 through a wireless/wired interface or store, inthe memory unit 130, information received through the wireless/wiredinterface from the exterior (e.g., other communication devices) via thecommunication unit 110.

The additional components 140 may be variously configured according totypes of wireless devices. For example, the additional components 140may include at least one of a power unit/battery, input/output (I/O)unit (e.g. audio I/O port, video I/O port), a driving unit, and acomputing unit. The wireless device may be implemented in the form of,without being limited to, the robot (100 a of FIG. 1 ), the vehicles(100 b-1 and 100 b-2 of FIG. 1 ), the XR device (100 c of FIG. 1 ), thehand-held device (100 d of FIG. 1 ), the home appliance (100 e of FIG. 1), the IoT device (100 f of FIG. 1 ), a digital broadcast terminal, ahologram device, a public safety device, an MTC device, a medicinedevice, a Fintech device (or a finance device), a security device, aclimate/environment device, the AI server/device (400 of FIG. 1 ), theBSs (200 of FIG. 1 ), a network node, etc. The wireless device may beused in a mobile or fixed place according to a use-example/service.

In FIG. 3 , the entirety of the various elements, components,units/portions, and/or modules in the wireless devices 100 and 200 maybe connected to each other through a wired interface or at least a partthereof may be wirelessly connected through the communication unit 110.For example, in each of the wireless devices 100 and 200, the controlunit 120 and the communication unit 110 may be connected by wire and thecontrol unit 120 and first units (e.g., 130 and 140) may be wirelesslyconnected through the communication unit 110. Each element, component,unit/portion, and/or module within the wireless devices 100 and 200 mayfurther include one or more elements. For example, the control unit 120may be configured by a set of one or more processors. As an example, thecontrol unit 120 may be configured by a set of a communication controlprocessor, an application processor, an electronic control unit (ECU), agraphical processing unit, and a memory control processor. As anotherexample, the memory 130 may be configured by a random access memory(RAM), a dynamic RAM (DRAM), a read only memory (ROM)), a flash memory,a volatile memory, a non-volatile memory, and/or a combination thereof.

FIGS. 4A and 4B illustrate examples of protocol stacks in a 3GPP basedwireless communication system.

In particular, FIG. 4A illustrates an example of a radio interface userplane protocol stack between a UE and a base station (BS) and FIG. 4Billustrates an example of a radio interface control plane protocol stackbetween a UE and a BS. The control plane refers to a path through whichcontrol messages used to manage call by a UE and a network aretransported. The user plane refers to a path through which datagenerated in an application layer, for example, voice data or Internetpacket data are transported. Referring to FIG. 4A, the user planeprotocol stack may be divided into a first layer (Layer 1) (i.e., aphysical (PHY) layer) and a second layer (Layer 2). Referring to FIG.4B, the control plane protocol stack may be divided into Layer 1 (i.e.,a PHY layer), Layer 2, Layer 3 (e.g., a radio resource control (RRC)layer), and a non-access stratum (NAS) layer. Layer 1, Layer 2 and Layer3 are referred to as an access stratum (AS).

The NAS control protocol is terminated in an access management function(AMF) on the network side, and performs functions such asauthentication, mobility management, security control and etc.

In the 3GPP LTE system, the layer 2 is split into the followingsublayers: medium access control (MAC), radio link control (RLC), andpacket data convergence protocol (PDCP). In the 3GPP New Radio (NR)system, the layer 2 is split into the following sublayers: MAC, RLC,PDCP and SDAP. The PHY layer offers to the MAC sublayer transportchannels, the MAC sublayer offers to the RLC sublayer logical channels,the RLC sublayer offers to the PDCP sublayer RLC channels, the PDCPsublayer offers to the SDAP sublayer radio bearers. The SDAP sublayeroffers to 5G Core Network quality of service (QoS) flows.

In the 3GPP NR system, the main services and functions of SDAP include:mapping between a QoS flow and a data radio bearer; marking QoS flow ID(QFI) in both DL and UL packets. A single protocol entity of SDAP isconfigured for each individual PDU session.

In the 3GPP NR system, the main services and functions of the RRCsublayer include: broadcast of system information related to AS and NAS;paging initiated by 5G core (5GC) or NG-RAN; establishment, maintenanceand release of an RRC connection between the UE and NG-RAN; securityfunctions including key management; establishment, configuration,maintenance and release of signalling radio bearers (SRBs) and dataradio bearers (DRBs); mobility functions (including: handover andcontext transfer; UE cell selection and reselection and control of cellselection and reselection; Inter-RAT mobility); QoS managementfunctions; UE measurement reporting and control of the reporting;detection of and recovery from radio link failure; NAS message transferto/from NAS from/to UE.

In the 3GPP NR system, the main services and functions of the PDCPsublayer for the user plane include: sequence numbering; headercompression and decompression: ROHC only; transfer of user data;reordering and duplicate detection; in-order delivery; PDCP PDU routing(in case of split bearers); retransmission of PDCP SDUs; ciphering,deciphering and integrity protection; PDCP SDU discard; PDCPre-establishment and data recovery for RLC AM; PDCP status reporting forRLC AM; duplication of PDCP PDUs and duplicate discard indication tolower layers. The main services and functions of the PDCP sublayer forthe control plane include: sequence numbering; ciphering, decipheringand integrity protection; transfer of control plane data; reordering andduplicate detection; in-order delivery; duplication of PDCP PDUs andduplicate discard indication to lower layers.

The RLC sublayer supports three transmission modes: Transparent Mode(TM); Unacknowledged Mode (UM); and Acknowledged Mode (AM). The RLCconfiguration is per logical channel with no dependency on numerologiesand/or transmission durations. In the 3GPP NR system, the main servicesand functions of the RLC sublayer depend on the transmission mode andinclude: Transfer of upper layer PDUs; sequence numbering independent ofthe one in PDCP (UM and AM); error correction through ARQ (AM only);segmentation (AM and UM) and re-segmentation (AM only) of RLC SDUs;reassembly of SDU (AM and UM); duplicate detection (AM only); RLC SDUdiscard (AM and UM); RLC re-establishment; protocol error detection (AMonly).

In the 3GPP NR system, the main services and functions of the MACsublayer include: mapping between logical channels and transportchannels; multiplexing/demultiplexing of MAC SDUs belonging to one ordifferent logical channels into/from transport blocks (TB) deliveredto/from the physical layer on transport channels; scheduling informationreporting; error correction through Hybrid automatic repeat request(HARQ) (one HARQ entity per cell in case of carrier aggregation (CA));priority handling between UEs by means of dynamic scheduling; priorityhandling between logical channels of one UE by means of logical channelprioritization; padding. A single MAC entity may support multiplenumerologies, transmission timings and cells. Mapping restrictions inlogical channel prioritization control which numerology(ies), cell(s),and transmission timing(s) a logical channel can use. Different kinds ofdata transfer services are offered by MAC. To accommodate differentkinds of data transfer services, multiple types of logical channels aredefined i.e. each supporting transfer of a particular type ofinformation. Each logical channel type is defined by what type ofinformation is transferred. Logical channels are classified into twogroups: Control Channels and Traffic Channels. Control channels are usedfor the transfer of control plane information only, and traffic channelsare used for the transfer of user plane information only. BroadcastControl Channel (BCCH) is a downlink logical channel for broadcastingsystem control information, paging Control Channel (PCCH) is a downlinklogical channel that transfers paging information, system informationchange notifications and indications of ongoing PWS broadcasts, CommonControl Channel (CCCH) is a logical channel for transmitting controlinformation between UEs and network and used for UEs having no RRCconnection with the network, and Dedicated Control Channel (DCCH) is apoint-to-point bi-directional logical channel that transmits dedicatedcontrol information between a UE and the network and used by UEs havingan RRC connection. Dedicated Traffic Channel (DTCH) is a point-to-pointlogical channel, dedicated to one UE, for the transfer of userinformation. A DTCH can exist in both uplink and downlink. In Downlink,the following connections between logical channels and transportchannels exist: BCCH can be mapped to BCH; BCCH can be mapped todownlink shared channel (DL-SCH); PCCH can be mapped to PCH; CCCH can bemapped to DL-SCH; DCCH can be mapped to DL-SCH; and DTCH can be mappedto DL-SCH. In Uplink, the following connections between logical channelsand transport channels exist: CCCH can be mapped to uplink sharedchannel (UL-SCH); DCCH can be mapped to UL-SCH; and DTCH can be mappedto UL-SCH.

FIG. 5 illustrates an example of a frame structure in a 3GPP basedwireless communication system.

The frame structure illustrated in FIG. 5 is purely exemplary and thenumber of subframes, the number of slots, and/or the number of symbolsin a frame may be variously changed. In the 3GPP based wirelesscommunication system, OFDM numerologies (e.g., subcarrier spacing (SCS),transmission time interval (TTI) duration) may be differently configuredbetween a plurality of cells aggregated for one UE. For example, if a UEis configured with different SCSs for cells aggregated for the cell, an(absolute time) duration of a time resource (e.g. a subframe, a slot, ora TTI) including the same number of symbols may be different among theaggregated cells. Herein, symbols may include OFDM symbols (or CP-OFDMsymbols), SC-FDMA symbols (or discrete Fourier transform-spread-OFDM(DFT-s-OFDM) symbols).

Referring to FIG. 5 , downlink and uplink transmissions are organizedinto frames. Each frame has T_(f)=10 ms duration. Each frame is dividedinto two half-frames, where each of the half-frames has 5 ms duration.Each half-frame consists of 5 subframes, where the duration T_(sf) persubframe is 1 ms. Each subframe is divided into slots and the number ofslots in a subframe depends on a subcarrier spacing. Each slot includes14 or 12 OFDM symbols based on a cyclic prefix (CP). In a normal CP,each slot includes 14 OFDM symbols and, in an extended CP, each slotincludes 12 OFDM symbols. The numerology is based on exponentiallyscalable subcarrier spacing Δf=2^(u)*15 kHz. The following table showsthe number of OFDM symbols per slot, the number of slots per frame, andthe number of slots per for the normal CP, according to the subcarrierspacing Δf=2^(u)*15 kHz.

TABLE 1 u N^(slot) _(symb) N^(frame, u) _(slot) N^(subframe, u) _(slot)0 14 10 1 1 14 20 2 2 14 40 4 3 14 80 8 4 14 160 16

The following table shows the number of OFDM symbols per slot, thenumber of slots per frame, and the number of slots per for the extendedCP, according to the subcarrier spacing Δf=2^(u)*15 kHz.

TABLE 2 u N^(slot) _(symb) N^(frame, u) _(slot) N^(subframe, u) _(slot)2 12 40 4

A slot includes plural symbols (e.g., 14 or 12 symbols) in the timedomain. For each numerology (e.g. subcarrier spacing) and carrier, aresource grid of N^(size,u) _(grid,x)*N^(RB) _(sc) subcarriers andN^(subframe,u) _(symb) OFDM symbols is defined, starting at commonresource block (CRB) N^(start,u) _(grid) indicated by higher-layersignaling (e.g. radio resource control (RRC) signaling), whereN^(size,u) _(grid,x) is the number of resource blocks in the resourcegrid and the subscript x is DL for downlink and UL for uplink. N^(RB)_(sc) is the number of subcarriers per resource blocks. In the 3GPPbased wireless communication system, N^(RB) _(sc) is 12 generally. Thereis one resource grid for a given antenna port p, subcarrier spacingconfiguration u, and transmission direction (DL or UL). The carrierbandwidth N^(size,u) _(grid) for subcarrier spacing configuration u isgiven by the higher-layer parameter (e.g. RRC parameter). Each elementin the resource grid for the antenna port p and the subcarrier spacingconfiguration u is referred to as a resource element (RE) and onecomplex symbol may be mapped to each RE. Each RE in the resource grid isuniquely identified by an index k in the frequency domain and an index lrepresenting a symbol location relative to a reference point in the timedomain. In the 3GPP based wireless communication system, a resourceblock is defined by 12 consecutive subcarriers in the frequency domain.

In the 3GPP NR system, resource blocks are classified into CRBs andphysical resource blocks (PRBs). CRBs are numbered from 0 and upwards inthe frequency domain for subcarrier spacing configuration u. The centerof subcarrier 0 of CRB 0 for subcarrier spacing configuration ucoincides with ‘point A’ which serves as a common reference point forresource block grids. In the 3GPP NR system, PRBs are defined within abandwidth part (BWP) and numbered from 0 to N^(size) _(BWP,i)−1, where iis the number of the bandwidth part. The relation between the physicalresource block n_(PRB) in the bandwidth part i and the common resourceblock n_(CRB) is as follows: n_(PRB)=n_(CRB)+N^(size) _(BWP,i), whereN^(size) _(BWP,i) is the common resource block where bandwidth partstarts relative to CRB 0. The BWP includes a plurality of consecutiveresource blocks. A carrier may include a maximum of N (e.g., 5) BWPs. AUE may be configured with one or more BWPs on a given component carrier.Only one BWP among BWPs configured to the UE can active at a time. Theactive BWP defines the UE's operating bandwidth within the cell'soperating bandwidth.

NR frequency bands are defined as 2 types of frequency range, FR1 andFR2. FR2 is may also called millimeter wave (mmW). The frequency rangesin which NR can operate are identified as described in Table 3.

TABLE 3 Frequency Range Corresponding Subcarrier designation frequencyrange Spacing FR1  450 MHz-7125 MHz  15, 30, 60 kHz FR2 24250 MHz-52600MHz 60, 120, 240 kHz

FIG. 6 illustrates a data flow example in the 3GPP NR system.

In FIG. 6 , “RB” denotes a radio bearer, and “H” denotes a header. Radiobearers are categorized into two groups: data radio bearers (DRB) foruser plane data and signalling radio bearers (SRB) for control planedata. The MAC PDU is transmitted/received using radio resources throughthe PHY layer to/from an external device. The MAC PDU arrives to the PHYlayer in the form of a transport block.

In the PHY layer, the uplink transport channels UL-SCH and RACH aremapped to physical uplink shared channel (PUSCH) and physical randomaccess channel (PRACH), respectively, and the downlink transportchannels DL-SCH, BCH and PCH are mapped to physical downlink sharedchannel (PDSCH), physical broad cast channel (PBCH) and PDSCH,respectively. In the PHY layer, uplink control information (UCI) ismapped to PUCCH, and downlink control information (DCI) is mapped toPDCCH. A MAC PDU related to UL-SCH is transmitted by a UE via a PUSCHbased on an UL grant, and a MAC PDU related to DL-SCH is transmitted bya BS via a PDSCH based on a DL assignment.

In order to transmit data unit(s) of the present disclosure on UL-SCH, aUE shall have uplink resources available to the UE. In order to receivedata unit(s) of the present disclosure on DL-SCH, a UE shall havedownlink resources available to the UE. The resource allocation includestime domain resource allocation and frequency domain resourceallocation. In the present disclosure, uplink resource allocation isalso referred to as uplink grant, and downlink resource allocation isalso referred to as downlink assignment. An uplink grant is eitherreceived by the UE dynamically on PDCCH, in a Random Access Response, orconfigured to the UE semi-persistently by RRC. Downlink assignment iseither received by the UE dynamically on the PDCCH, or configured to theUE semi-persistently by RRC signaling from the BS.

In UL, the BS can dynamically allocate resources to UEs via the CellRadio Network Temporary Identifier (C-RNTI) on PDCCH(s). A UE alwaysmonitors the PDCCH(s) in order to find possible grants for uplinktransmission when its downlink reception is enabled (activity governedby discontinuous reception (DRX) when configured). In addition, withConfigured Grants, the BS can allocate uplink resources for the initialHARQ transmissions to UEs. Two types of configured uplink grants aredefined: Type 1 and Type 2. With Type 1, RRC directly provides theconfigured uplink grant (including the periodicity). With Type 2, RRCdefines the periodicity of the configured uplink grant while PDCCHaddressed to Configured Scheduling RNTI (CS-RNTI) can either signal andactivate the configured uplink grant, or deactivate it; i.e. a PDCCHaddressed to CS-RNTI indicates that the uplink grant can be implicitlyreused according to the periodicity defined by RRC, until deactivated.

In DL, the BS can dynamically allocate resources to UEs via the C-RNTIon PDCCH(s). A UE always monitors the PDCCH(s) in order to find possibleassignments when its downlink reception is enabled (activity governed byDRX when configured). In addition, with Semi-Persistent Scheduling(SPS), the BS can allocate downlink resources for the initial HARQtransmissions to UEs: RRC defines the periodicity of the configureddownlink assignments while PDCCH addressed to CS-RNTI can either signaland activate the configured downlink assignment, or deactivate it. Inother words, a PDCCH addressed to CS-RNTI indicates that the downlinkassignment can be implicitly reused according to the periodicity definedby RRC, until deactivated.

<Resource Allocation by PDCCH (i.e. Resource Allocation by DCI)>

PDCCH can be used to schedule DL transmissions on PDSCH and ULtransmissions on PUSCH, where the downlink control information (DCI) onPDCCH includes: downlink assignments containing at least modulation andcoding format (e.g., modulation and coding scheme (MCS) index IMCS),resource allocation, and hybrid-ARQ information related to DL-SCH; oruplink scheduling grants containing at least modulation and codingformat, resource allocation, and hybrid-ARQ information related toUL-SCH. The size and usage of the DCI carried by one PDCCH are varieddepending on DCI formats. For example, in the 3GPP NR system, DCI format0_0 or DCI format 0_1 is used for scheduling of PUSCH in one cell, andDCI format 1_0 or DCI format 1_1 is used for scheduling of PDSCH in onecell.

FIGS. 7A and 7B illustrate examples of PDSCH time domain resourceallocation by PDCCH, and an example of PUSCH time resource allocation byPDCCH.

Downlink control information (DCI) carried by a PDCCH for schedulingPDSCH or PUSCH includes a value m for a row index m+1 to an allocationtable for PDSCH or PUSCH. Either a predefined default PDSCH time domainallocation A, B or C is applied as the allocation table for PDSCH, orRRC configured pdsch-TimeDomainAllocationList is applied as theallocation table for PDSCH. Either a predefined default PUSCH timedomain allocation A is applied as the allocation table for PUSCH, or theRRC configured pusch-TimeDomainAllocationList is applied as theallocation table for PUSCH. Which PDSCH time domain resource allocationconfiguration to apply and which PUSCH time domain resource allocationtable to apply are determined according to a fixed/predefined rule (e.g.Table 5.1.2.1.1-1 in 3GPP TS 38.214 v15.3.0, Table 6.1.2.1.1-1 in 3GPPTS 38.214 v15.3.0).

Each indexed row in PDSCH time domain allocation configurations definesthe slot offset K₀, the start and length indicator SLIV, or directly thestart symbol S and the allocation length L, and the PDSCH mapping typeto be assumed in the PDSCH reception. Each indexed row in PUSCH timedomain allocation configurations defines the slot offset K₂, the startand length indicator SLIV, or directly the start symbol S and theallocation length L, and the PUSCH mapping type to be assumed in thePUSCH reception. K₀ for PDSCH, or K₂ for PUSCH is the timing differencebetween a slot with a PDCCH and a slot with PDSCH or PUSCH correspondingto the PDCCH. SLIV is a joint indication of starting symbol S relativeto the start of the slot with PDSCH or PUSCH, and the number L ofconsecutive symbols counting from the symbol S. For PDSCH/PUSCH mappingtype, there are two mapping types: one is Mapping Type A wheredemodulation reference signal (DMRS) is positioned in 3^(rd) or 4^(th)symbol of a slot depending on the RRC signaling, and other one isMapping Type B where DMRS is positioned in the first allocated symbol.

The scheduling DCI includes the Frequency domain resource assignmentfield which provides assignment information on resource blocks used forPDSCH or PUSCH. For example, the Frequency domain resource assignmentfield may provide a UE with information on a cell for PDSCH or PUSCHtransmission, information on a bandwidth part for PDSCH or PUSCHtransmission, information on resource blocks for PDSCH or PUSCHtransmission.

<Resource Allocation by RRC>

As mentioned above, in uplink, there are two types of transmissionwithout dynamic grant: configured grant Type 1 where an uplink grant isprovided by RRC, and stored as configured grant; and configured grantType 2 where an uplink grant is provided by PDCCH, and stored or clearedas configured uplink grant based on L1 signaling indicating configureduplink grant activation or deactivation. Type 1 and Type 2 areconfigured by RRC per serving cell and per BWP. Multiple configurationscan be active simultaneously only on different serving cells. For Type2, activation and deactivation are independent among the serving cells.For the same serving cell, the MAC entity is configured with either Type1 or Type 2.

A UE is provided with at least the following parameters via RRCsignaling from a BS when the configured grant type 1 is configured:

-   -   cs-RNTI which is CS-RNTI for retransmission;    -   periodicity which provides periodicity of the configured grant        Type 1;    -   timeDomainOffset which represents offset of a resource with        respect to SFN=0 in time domain;    -   timeDomainAllocation value m which provides a row index m+1        pointing to an allocation table, indicating a combination of a        start symbol S and length L and PUSCH mapping type;    -   frequencyDomainAllocation which provides frequency domain        resource allocation; and    -   mcsAndTBS which provides IMCS representing the modulation order,        target code rate and transport block size. Upon configuration of        a configured grant Type 1 for a serving cell by RRC, the UE        stores the uplink grant provided by RRC as a configured uplink        grant for the indicated serving cell, and initialise or        re-initialise the configured uplink grant to start in the symbol        according to timeDomainOffset and S (derived from SLIV), and to        reoccur with periodicity. After an uplink grant is configured        for a configured grant Type 1, the UE considers that the uplink        grant recurs associated with each symbol for which:        [(SFN*numberOfSlotsPerFrame (numberOfSymbolsPerSlot)+(slot        number in the frame×numberOfSymbolsPerSlot)+symbol number in the        slot]=(timeDomainOffset*numberOfSymbolsPerSlot+S+N*periodicity)modulo(1024*numberOfSlotsPerFrame*numberOfSymbolsPerSlot),        for all N>=0.

A UE is provided with at least the following parameters via RRCsignaling from a BS when the configured gran Type 2 is configured:

-   -   cs-RNTI which is CS-RNTI for activation, deactivation, and        retransmission; and    -   periodicity which provides periodicity of the configured grant        Type 2. The actual uplink grant is provided to the UE by the        PDCCH (addressed to CS-RNTI). After an uplink grant is        configured for a configured grant Type 2, the UE considers that        the uplink grant recurs associated with each symbol for which:        [(SFN*numberOfSlotsPerFrame*numberOfSymbolsPerSlot)+(slot number        in the frame*numberOfSymbolsPerSlot)+symbol number in the        slot]=[(SFN_(start time)*numberOfSlotsPerFrame*numberOfSymbolsPerSlot+Slot_(start time)*numberOfSymbolsPerSlot+symbol_(start time))N*periodicity]modulo(1024×numberOfSlotsPerFrame*numberOfSymbolsPerSlot),        for all N>=0, where SFN_(start time), slot_(start time), and        symbol_(start time) are the SFN, slot, and symbol, respectively,        of the first transmission opportunity of PUSCH where the        configured uplink grant was (re-)initialised.        numberOfSlotsPerFrame and numberOfSymbolsPerSlot refer to the        number of consecutive slots per frame and the number of        consecutive OFDM symbols per slot, respectively (see Table 1 and        Table 1).

For configured uplink grants, the HARQ Process ID associated with thefirst symbol of a UL transmission is derived from the followingequation:

HARQ Process ID=[floor(CURRENT_symbol/periodicity)]modulonrofHARQ-Processes

whereCURRENT_symbol=(SFN×numberOfSlotsPerFrame×numberOfSymbolsPerSlot+slotnumber in the frame×numberOfSymbolsPerSlot+symbol number in the slot),and numberOfSlotsPerFrame and numberOfSymbolsPerSlot refer to the numberof consecutive slots per frame and the number of consecutive symbols perslot, respectively as specified in TS 38.211. CURRENT_symbol refers tothe symbol index of the first transmission occasion of a repetitionbundle that takes place. A HARQ process is configured for a configureduplink grant if the configured uplink grant is activated and theassociated HARQ process ID is less than nrofHARQ-Processes.

For downlink, a UE may be configured with semi-persistent scheduling(SPS) per serving cell and per BWP by RRC signaling from a BS. Multipleconfigurations can be active simultaneously only on different servingcells. Activation and deactivation of the DL SPS are independent amongthe serving cells. For DL SPS, a DL assignment is provided to the UE byPDCCH, and stored or cleared based on L1 signaling indicating SPSactivation or deactivation. A UE is provided with the followingparameters via RRC signaling from a BS when SPS is configured:

-   -   cs-RNTI which is CS-RNTI for activation, deactivation, and        retransmission;    -   nrofHARQ-Processes: which provides the number of configured HARQ        processes for SPS;    -   periodicity which provides periodicity of configured downlink        assignment for SPS.

When SPS is released by upper layers, all the correspondingconfigurations shall be released.

After a downlink assignment is configured for SPS, the UE considerssequentially that the N^(th) downlink assignment occurs in the slot forwhich: (numberOfSlotsPerFrame*SFN+slot number in theframe)=[(numberOfSlotsPerFrame*SFN_(start time)+slot_(start time))+N*periodicity*numberOfSlotsPerFrame/10]modulo(1024*numberOfSlotsPerFrame), where SFN_(start time) andslot_(start time) are the SFN and slot, respectively, of the firsttransmission of PDSCH where the configured downlink assignment was(re-)initialised.

For configured downlink assignments, the HARQ Process ID associated withthe slot where the DL transmission starts is derived from the followingequation:

HARQ ProcessID=[floor(CURRENT_slot×10/(numberOfSlotsPerFrame×periodicity))]modulonrofHARQ-Processes

where CURRENT_slot=[(SFN×numberOfSlotsPerFrame)+slot number in theframe] and numberOfSlotsPerFrame refers to the number of consecutiveslots per frame as specified in TS 38.211.

A UE validates, for scheduling activation or scheduling release, a DLSPS assignment PDCCH or configured UL grant type 2 PDCCH if the cyclicredundancy check (CRC) of a corresponding DCI format is scrambled withCS-RNTI provided by the RRC parameter cs-RNTI and the new data indicatorfield for the enabled transport block is set to 0. Validation of the DCIformat is achieved if all fields for the DCI format are set according toTable 4 or Table 5. Table 4 shows special fields for DL SPS and UL grantType 2 scheduling activation PDCCH validation, and Table 5 shows specialfields for DL SPS and UL grant Type 2 scheduling release PDCCHvalidation.

TABLE 4 DCI format DCI format DCI format 0_0/0_1 1_0 1_1 HARQ processset to all ‘0’s set to all ‘0’s set to all ‘0’s number Redundancy set to‘00’ set to ‘00’ For the enabled version transport block: set to ‘00’

TABLE 5 DCI format DCI format 0_0 1_0 HARQ process number set to all‘0’s set to all ‘0’s Redundancy version set to ‘00’ set to ‘00’Modulation and coding scheme set to all ‘1’s set to all ‘1’s Resourceblock assignment set to all ‘1’s set to all ‘1’s

Actual DL assignment and actual UL grant, and the correspondingmodulation and coding scheme are provided by the resource assignmentfields (e.g. time domain resource assignment field which provides Timedomain resource assignment value m, frequency domain resource assignmentfield which provides the frequency resource block allocation, modulationand coding scheme field) in the DCI format carried by the DL SPS and ULgrant Type 2 scheduling activation PDCCH. If validation is achieved, theUE considers the information in the DCI format as valid activation orvalid release of DL SPS or configured UL grant Type 2.

For UL, the processor(s) 102 of the present disclosure may transmit (orcontrol the transceiver(s) 106 to transmit) the data unit of the presentdisclosure based on the UL grant available to the UE. The processor(s)202 of the present disclosure may receive (or control the transceiver(s)206 to receive) the data unit of the present disclosure based on the ULgrant available to the UE.

For DL, the processor(s) 102 of the present disclosure may receive (orcontrol the transceiver(s) 106 to receive) DL data of the presentdisclosure based on the DL assignment available to the UE. Theprocessor(s) 202 of the present disclosure may transmit (or control thetransceiver(s) 206 to transmit) DL data of the present disclosure basedon the DL assignment available to the UE.

The data unit(s) of the present disclosure is(are) subject to thephysical layer processing at a transmitting side before transmission viaradio interface, and the radio signals carrying the data unit(s) of thepresent disclosure are subject to the physical layer processing at areceiving side. For example, a MAC PDU including the PDCP PDU accordingto the present disclosure may be subject to the physical layerprocessing as follows.

FIG. 8 illustrates an example of physical layer processing at atransmitting side.

The following tables show the mapping of the transport channels (TrCHs)and control information to its corresponding physical channels. Inparticular, Table 6 specifies the mapping of the uplink transportchannels to their corresponding physical channels, Table 7 specifies themapping of the uplink control channel information to its correspondingphysical channel, Table 8 specifies the mapping of the downlinktransport channels to their corresponding physical channels, and Table 9specifies the mapping of the downlink control channel information to itscorresponding physical channel.

TABLE 6 TrCH Physical Channel UL-SCH PUSCH RACH PRACH

TABLE 7 Control information Physical Channel UCI PUCCH, PUSCH

TABLE 8 TrCH Physical Channel DL-SCH PDSCH BCH PBCH PCH PDSCH

TABLE 9 Control information Physical Channel DCI PDCCH

<Encoding>

Data and control streams from/to MAC layer are encoded to offertransport and control services over the radio transmission link in thePHY layer. For example, a transport block from MAC layer is encoded intoa codeword at a transmitting side. Channel coding scheme is acombination of error detection, error correcting, rate matching,interleaving and transport channel or control information mappingonto/splitting from physical channels.

In the 3GPP NR system, following channel coding schemes are used for thedifferent types of TrCH and the different control information types.

TABLE 10 TrCH Coding scheme UL-SCH LDPC DL-SCH PCH BCH Polar code

TABLE 11 Control Information Coding scheme DCI Polar code UCI Block codePolar code

For transmission of a DL transport block (i.e. a DL MAC PDU) or a ULtransport block (i.e. a UL MAC PDU), a transport block CRC sequence isattached to provide error detection for a receiving side. In the 3GPP NRsystem, the communication device uses low density parity check (LDPC)codes in encoding/decoding UL-SCH and DL-SCH. The 3GPP NR systemsupports two LDPC base graphs (i.e. two LDPC base matrixes): LDPC basegraph 1 optimized for small transport blocks and LDPC base graph 2 forlarger transport blocks. Either LDPC base graph 1 or 2 is selected basedon the size of the transport block and coding rate R. The coding rate Ris indicated by the modulation coding scheme (MCS) index IMCS. The MCSindex is dynamically provided to a UE by PDCCH scheduling PUSCH orPDSCH, provided to a UE by PDCCH activating or (re-)initializing the ULconfigured grant 2 or DL SPS, or provided to a UE by RRC signalingrelated to the UL configured grant Type 1. If the CRC attached transportblock is larger than the maximum code block size for the selected LDPCbase graph, the CRC attached transport block may be segmented into codeblocks, and an additional CRC sequence is attached to each code block.The maximum code block sizes for the LDPC base graph 1 and the LDPC basegraph 2 are 8448 bits and 3480 bits, respectively. If the CRC attachedtransport block is not larger than the maximum code block size for theselected LDPC base graph, the CRC attached transport block is encodedwith the selected LDPC base graph. Each code block of the transportblock is encoded with the selected LDPC base graph. The LDPC codedblocks are then individually rat matched. Code block concatenation isperformed to create a codeword for transmission on PDSCH or PUSCH. ForPDSCH, up to 2 codewords (i.e. up to 2 transport blocks) can betransmitted simultaneously on the PDSCH. PUSCH can be used fortransmission of UL-SCH data and layer 1/2 control information. Althoughnot shown in FIG. 8 , the layer 1/2 control information may bemultiplexed with the codeword for UL-SCH data.

<Scrambling and Modulation>

The bits of the codeword are scrambled and modulated to generate a blockof complex-valued modulation symbols.

<Layer Mapping>

The complex-valued modulation symbols of the codeword are mapped to oneor more multiple input multiple output (MIMO) layers. A codeword can bemapped to up to 4 layers. A PDSCH can carry two codewords, and thus aPDSCH can support up to 8-layer transmission. A PUSCH supports a singlecodeword, and thus a PUSCH can support up to 4-layer transmission.

<Transform Precoding>

The DL transmission waveform is conventional OFDM using a cyclic prefix(CP). For DL, transform precoding (in other words, discrete Fouriertransform (DFT)) is not applied.

The UL transmission waveform is conventional OFDM using a CP with atransform precoding function performing DFT spreading that can bedisabled or enabled. In the 3GPP NR system, for UL, the transformprecoding can be optionally applied if enabled. The transform precodingis to spread UL data in a special way to reduce peak-to-average powerratio (PAPR) of the waveform. The transform precoding is a form of DFT.In other words, the 3GPP NR system supports two options for UL waveform:one is CP-OFDM (same as DL waveform) and the other one is DFT-s-OFDM.Whether a UE has to use CP-OFDM or DFT-s-OFDM is configured by a BS viaRRC parameters.

<Subcarrier Mapping>

The layers are mapped to antenna ports. In DL, for the layers to antennaports mapping, a transparent manner (non-codebook based) mapping issupported and how beamforming or MIMO precoding is performed istransparent to the UE. In UL, for the layers to antenna ports mapping,both the non-codebook based mapping and a codebook based mapping aresupported.

For each antenna port (i.e. layer) used for transmission of the physicalchannel (e.g. PDSCH, PUSCH), the complex-valued modulation symbols aremapped to subcarriers in resource blocks allocated to the physicalchannel.

<OFDM Modulation>

The communication device at the transmitting side generates atime-continuous OFDM baseband signal on antenna port p and subcarrierspacing configuration u for OFDM symbol 1 in a TTI for a physicalchannel by adding a cyclic prefix (CP) and performing IFFT. For example,for each OFDM symbol, the communication device at the transmitting sidemay perform inverse fast Fourier transform (IFFT) on the complex-valuedmodulation symbols mapped to resource blocks in the corresponding OFDMsymbol and add a CP to the IFFT-ed signal to generate the OFDM basebandsignal.

<Up-Conversion>

The communication device at the transmitting side up-convers the OFDMbaseband signal for antenna port p, subcarrier spacing configuration uand OFDM symbol l to a carrier frequency f₀ of a cell to which thephysical channel is assigned.

The processors 102 and 202 in FIG. 2 may be configured to performencoding, schrambling, modulation, layer mapping, transform precoding(for UL), subcarrier mapping, and OFDM modulation. The processors 102and 202 may control the transceivers 106 and 206 connected to theprocessors 102 and 202 to up-convert the OFDM baseband signal onto thecarrier frequency to generate radio frequency (RF) signals. The radiofrequency signals are transmitted through antennas 108 and 208 to anexternal device.

FIG. 9 illustrates an example of physical layer processing at areceiving side.

The physical layer processing at the receiving side is basically theinverse processing of the physical layer processing at the transmittingside.

<Frequency Down-Conversion>

The communication device at a receiving side receives RF signals at acarrier frequency through antennas. The transceivers 106 and 206receiving the RF signals at the carrier frequency down-converts thecarrier frequency of the RF signals into the baseband in order to obtainOFDM baseband signals.

<OFDM Demodulation>

The communication device at the receiving side obtains complex-valuedmodulation symbols via CP detachment and FFT. For example, for each OFDMsymbol, the communication device at the receiving side removes a CP fromthe OFDM baseband signals and performs FFT on the CP-removed OFDMbaseband signals to obtain complex-valued modulation symbols for antennaport p, subcarrier spacing u and OFDM symbol 1.

<Subcarrier Demapping>

The subcarrier demapping is performed on the complex-valued modulationsymbols to obtain complex-valued modulation symbols of a correspondingphysical channel. For example, the processor(s) 102 may obtaincomplex-valued modulation symbols mapped to subcarriers belong to PDSCHfrom among complex-valued modulation symbols received in a bandwidthpart. For another example, the processor(s) 202 may obtaincomplex-valued modulation symbols mapped to subcarriers belong to PUSCHfrom among complex-valued modulation symbols received in a bandwidthpart.

<Transform De-Precoding>

Transform de-precoding (e.g. IDFT) is performed on the complex-valuedmodulation symbols of the uplink physical channel if the transformprecoding has been enabled for the uplink physical channel. For thedownlink physical channel and for the uplink physical channel for whichthe transform precoding has been disabled, the transform de-precoding isnot performed.

<Layer Demapping>

The complex-valued modulation symbols are de-mapped into one or twocodewords.

<Demodulation and Descrambling>

The complex-valued modulation symbols of a codeword are demodulated anddescrambled into bits of the codeword.

<Decoding>

The codeword is decoded into a transport block. For UL-SCH and DL-SCH,either LDPC base graph 1 or 2 is selected based on the size of thetransport block and coding rate R. The codeword may include one ormultiple coded blocks. Each coded block is decoded with the selectedLDPC base graph into a CRC-attached code block or CRC-attached transportblock. If code block segmentation was performed on a CRC-attachedtransport block at the transmitting side, a CRC sequence is removed fromeach of CRC-attached code blocks, whereby code blocks are obtained. Thecode blocks are concatenated into a CRC-attached transport block. Thetransport block CRC sequence is removed from the CRC-attached transportblock, whereby the transport block is obtained. The transport block isdelivered to the MAC layer.

In the above described physical layer processing at the transmitting andreceiving sides, the time and frequency domain resources (e.g. OFDMsymbol, subcarriers, carrier frequency) related to subcarrier mapping,OFDM modulation and frequency up/down conversion can be determined basedon the resource allocation (e.g., UL grant, DL assignment).

For uplink data transmission, the processor(s) 102 of the presentdisclosure may apply (or control the transceiver(s) 106 to apply) theabove described physical layer processing of the transmitting side tothe data unit of the present disclosure to transmit the data unitwirelessly. For downlink data reception, the processor(s) 102 of thepresent disclosure may apply (or control the transceiver(s) 106 toapply) the above described physical layer processing of the receivingside to received radio signals to obtain the data unit of the presentdisclosure.

For downlink data transmission, the processor(s) 202 of the presentdisclosure may apply (or control the transceiver(s) 206 to apply) theabove described physical layer processing of the transmitting side tothe data unit of the present disclosure to transmit the data unitwirelessly. For uplink data reception, the processor(s) 202 of thepresent disclosure may apply (or control the transceiver(s) 206 toapply) the above described physical layer processing of the receivingside to received radio signals to obtain the data unit of the presentdisclosure.

FIG. 10 illustrates operations of the wireless devices based on theimplementations of the present disclosure.

The first wireless device 100 of FIG. 2 may generate firstinformation/signals according to the functions, procedures, and/ormethods described in the present disclosure, and then transmit radiosignals including the first information/signals wirelessly to the secondwireless device 200 of FIG. 2 (S10). The first information/signals mayinclude the data unit(s) (e.g. PDU, SDU, RRC message) of the presentdisclosure. The first wireless device 100 may receive radio signalsincluding second information/signals from the second wireless device 200(S30), and then perform operations based on or according to the secondinformation/signals (S50). The second information/signals may betransmitted by the second wireless device 200 to the first wirelessdevice 100 in response to the first information/signals. The secondinformation/signals may include the data unit(s) (e.g. PDU, SDU, RRCmessage) of the present disclosure. The first information/signals mayinclude contents request information, and the second information/signalsmay include contents specific to the usage of the first wireless device100. Some examples of operations specific to the usages of the wirelessdevices 100 and 200 will be described below.

In some scenarios, the first wireless device 100 may be a hand-helddevice 100 d of FIG. 1 , which performs the functions, procedures,and/or methods described in the present disclosure. The hand-held device100 d may acquire information/signals (e.g., touch, text, voice, images,or video) input by a user, and convert the acquired information/signalsinto the first information/signals. The hand-held devices 100 d maytransmit the first information/signals to the second wireless device 200(S10). The second wireless device 200 may be any one of the wirelessdevices 100 a to 100 f in FIG. 1 or a BS. The hand-held device 100 d mayreceive the second information/signals from the second wireless device200 (S30), and perform operations based on the secondinformation/signals (S50). For example, the hand-held device 100 d mayoutput the contents of the second information/signals to the user (e.g.in the form of text, voice, images, video, or haptic) through the I/Ounit of the hand-held device 100 d.

In some scenarios, the first wireless device 100 may be a vehicle or anautonomous driving vehicle 100 b, which performs the functions,procedures, and/or methods described in the present disclosure. Thevehicle 100 b may transmit (S10) and receive (S30) signals (e.g. dataand control signals) to and from external devices such as othervehicles, BSs (e.g. gNBs and road side units), and servers, through itscommunication unit (e.g. communication unit 110 of FIG. 1C). The vehicle100 b may include a driving unit, and the driving unit may cause thevehicle 100 b to drive on a road. The driving unit of the vehicle 100 bmay include an engine, a motor, a powertrain, a wheel, a brake, asteering device, etc. The vehicle 100 b may include a sensor unit foracquiring a vehicle state, ambient environment information, userinformation, etc. The vehicle 100 b may generate and transmit the firstinformation/signals to the second wireless device 200 (S10). The firstinformation/signals may include vehicle state information, ambientenvironment information, user information, and etc. The vehicle 100 bmay receive the second information/signals from the second wirelessdevice 200 (S30). The second information/signals may include vehiclestate information, ambient environment information, user information,and etc. The vehicle 100 b may drive on a road, stop, or adjust speed,based on the second information/signals (S50). For example, the vehicle100 b may receive map the second information/signals including data,traffic information data, etc. from an external server (S30). Thevehicle 100 b may generate an autonomous driving path and a driving planbased on the second information/signals, and may move along theautonomous driving path according to the driving plan (e.g.,speed/direction control) (S50). For another example, the control unit orprocessor(s) of the vehicle 100 b may generate a virtual object based onthe map information, traffic information, and vehicle positioninformation obtained through a GPS sensor of the vehicle 100 b and anI/O unit 140 of the vehicle 100 b may display the generated virtualobject in a window in the vehicle 100 b (S50).

In some scenarios, the first wireless device 100 may be an XR device 100c of FIG. 1 , which performs the functions, procedures, and/or methodsdescribed in the present disclosure. The XR device 100 c may transmit(S10) and receive (S30) signals (e.g., media data and control signals)to and from external devices such as other wireless devices, hand-helddevices, or media servers, through its communication unit (e.g.communication unit 110 of FIG. 1C). For example, the XR device 100 ctransmits content request information to another device or media server(S10), and download/stream contents such as films or news from anotherdevice or the media server (S30), and generate, output or display an XRobject (e.g. an AR/VR/MR object), based on the secondinformation/signals received wirelessly, through an I/O unit of the XRdevice (S50).

In some scenarios, the first wireless device 100 may be a robot 100 a ofFIG. 1 , which performs the functions, procedures, and/or methodsdescribed in the present disclosure. The robot 100 a may be categorizedinto an industrial robot, a medical robot, a household robot, a militaryrobot, etc., according to a used purpose or field. The robot 100 a maytransmit (S10) and receive (S30) signals (e.g., driving information andcontrol signals) to and from external devices such as other wirelessdevices, other robots, or control servers, through its communicationunit (e.g. communication unit 110 of FIG. 1C). The secondinformation/signals may include driving information and control signalsfor the robot 100 a. The control unit or processor(s) of the robot 100 amay control the movement of the robot 100 a based on the secondinformation/signals.

In some scenarios, the first wireless device 100 may be an AI device 400of FIG. 1 . The AI device may be implemented by a fixed device or amobile device, such as a TV, a projector, a smartphone, a PC, anotebook, a digital broadcast terminal, a tablet PC, a wearable device,a Set Top Box (STB), a radio, a washing machine, a refrigerator, adigital signage, a robot, a vehicle, etc. The AI device 400 may transmit(S10) and receive (S30) wired/radio signals (e.g., sensor information,user input, learning models, or control signals) to and from externaldevices such as other AI devices (e.g., 100 a, . . . , 100 f, 200, or400 of FIG. 1 ) or an AI server (e.g., 400 of FIG. 1 ) usingwired/wireless communication technology. The control unit orprocessor(s) of the AI device 400 may determine at least one feasibleoperation of the AI device 400, based on information which is determinedor generated using a data analysis algorithm or a machine learningalgorithm. The AI device 400 may request that external devices such asother AI devices or AI server provide the AI device 400 with sensorinformation, user input, learning models, control signals and etc.(S10). The AI device 400 may receive second information/signals (e.g.,sensor information, user input, learning models, or control signals)(S30), and the AI device 400 may perform a predicted operation or anoperation determined to be preferred among at least one feasibleoperation based on the second information/signals (S50).

Hereinafter, it is described about maintenance of Uplink Time Alignment.

Firstly, for the maintenance of UL time alignment, the RRC configurestimeAlignmentTimer (per Timing Advance Group (TAG)) which controls howlong the MAC entity considers the Serving Cells belonging to theassociated TAG to be uplink time aligned.

When a Timing Advance Command MAC CE is received, and if an N_(TA) hasbeen maintained with the indicated TAG, the MAC entity shall apply theTiming Advance Command for the indicated TAG, and start or restart thetimeAlignmentTimer associated with the indicated TAG.

When a Timing Advance Command is received in a Random Access Responsemessage for a Serving Cell belonging to a TAG or in a MSGB for anSpCell, if the Random Access Preamble was not selected by the MAC entityamong the contention-based Random Access Preamble, the MAC entity shallapply the Timing Advance Command for this TAG, and start or restart thetimeAlignmentTimer associated with this TAG.

Else if the timeAlignmentTimer associated with this TAG is not running,the MAC entity shall apply the Timing Advance Command for this TAG, andstart the timeAlignmentTimer associated with this TAG. Further, when theContention Resolution is considered not successful or when theContention Resolution is considered successful for SI request, aftertransmitting HARQ feedback for MAC PDU including UE ContentionResolution Identity MAC CE, the MAC entity shall stop timeAlignmentTimerassociated with this TAG.

Else, the MAC entity shall ignore the received Timing Advance Command.

When an Absolute Timing Advance Command is received in response to aMSGA transmission including C-RNTI MAC CE, the MAC entity shall applythe Timing Advance Command for PTAG, and start or restart thetimeAlignmentTimer associated with PTAG.

When a timeAlignmentTimer expires, if the timeAlignmentTimer isassociated with the PTAG, the MAC entity shall:

-   -   flush all HARQ buffers for all Serving Cells; notify RRC to        release PUCCH for all Serving Cells, if configured;    -   notify RRC to release SRS for all Serving Cells, if configured;    -   clear any configured downlink assignments and configured uplink        grants;    -   clear any PUSCH resource for semi-persistent CSI reporting;    -   consider all running timeAlignmentTimers as expired;    -   maintain N_(TA) of all TAGs.

Else if the timeAlignmentTimer is associated with an STAG, then for allServing Cells belonging to this TAG: the MAC entity shall:

-   -   flush all HARQ buffers;    -   notify RRC to release PUCCH, if configured;    -   notify RRC to release SRS, if configured;    -   clear any configured downlink assignments and configured uplink        grants;    -   clear any PUSCH resource for semi-persistent CSI reporting;    -   maintain NTA of this TAG.

When the MAC entity stops uplink transmissions for an SCell due to thefact that the maximum uplink transmission timing difference between TAGsof the MAC entity or the maximum uplink transmission timing differencebetween TAGs of any MAC entity of the UE is exceeded, the MAC entityconsiders the timeAlignmentTimer associated with the SCell as expired.

The MAC entity shall not perform any uplink transmission on a ServingCell except the Random Access Preamble and MSGA transmission when thetimeAlignmentTimer associated with the TAG to which this Serving Cellbelongs is not running. Furthermore, when the timeAlignmentTimerassociated with the PTAG is not running, the MAC entity shall notperform any uplink transmission on any Serving Cell except the RandomAccess Preamble and MSGA transmission on the SpCell.

FIG. 11 shows an example of Timing Advance Command MAC CE in the NRsystem.

Referring to FIG. 11 , the Timing Advance Command MAC CE is identifiedby MAC subheader with LCID. It has a fixed size and consists of a singleoctet defined as follows:

-   -   TAG Identity (TAG ID): This field indicates the TAG Identity of        the addressed TAG. The TAG containing the SpCell has the TAG        Identity 0. The length of the field is 2 bits;    -   Timing Advance Command: This field indicates the index value TA        (0, 1, 2 . . . 63) used to control the amount of timing        adjustment that MAC entity has to apply. The length of the field        is 6 bits.

FIG. 12 shows an example of Absolute Timing Advance Command MAC CE inthe NR system.

Referring to FIG. 12 , the Absolute Timing Advance Command MAC CE isidentified by MAC subheader with eLCID. It has a fixed size and consistsof two octets defined as follows:

-   -   Timing Advance Command: This field indicates the index value TA        used to control the amount of timing adjustment that the MAC        entity has to apply. The size of the field is 12 bits;    -   R: Reserved bit, set to “0”.

As mentioned above, the Time Alignment Timer (TAT) is used to controlhow long the UE considers the Serving Cells belonging to the associatedTiming Advance Group (TAG) to be uplink time aligned with the network.The TAT is maintained per TAG.

While the TAT is running, the UE considers that the uplink time isaligned with the network, and can perform UL transmission. However, ifthe TAT expires, the UE flushes all HARQ buffers for all serving cellsbelonging to the TAG, and also releases PUCCH/SRS resources, clears anyconfigured downlink assignments and configured uplink grants, etc. Asall the UL resources are cleared at TAT expiry, the UE cannot perform ULtransmission if the TAT is not running.

If the UE wants to perform UL transmission while the TAT is not running,the UE must perform Random Access (RA) procedure first to obtain a validuplink timing. After that, the UE must obtain the valid UL resource fromthe network. Therefore, once the TAT expires, there would be large delayuntil the UE performs UL transmission. To avoid such large delay in ULtransmission, the UE must maintain the TAT running if the UE expects ULtransmission in a near future.

However, the network may not know the TAT status of the UE correctly.The UE starts or restarts the TAT when a Timing Advance Command (TAC)MAC CE or an Absolute TAC MAC CE is received or a RAR which includesTiming Advance Command is received. If the MAC PDU including the TAC issuccessfully received, the UE starts the TAT upon reception of the MACPDU. However, if the HARQ feedback of the MAC PDU is successfullytransmitted only after a number of transmission, the network considersthat the TAT of the UE starts only at the time when the HARQ feedback issuccessfully received. Therefore, there would be de-synchronizationbetween the UE and the network regarding the start time of the TAT, i.e.the UE may start the TAT much earlier than the network considers. Inthis case, the UE's TAT expires, which is unexpected by the network.

To avoid delay in UL transmission due to unwanted TAT expiry, it isinvented that the UE reports the TAT status to the network when there isnot much remaining time of the TAT until the expiry but the UE wants tokeep the TAT running for the provision of potential UL transmission.

The UE triggers the TAT status report when the remaining time of the TATuntil the expiry is less than a configured threshold (e.g., TH_TAT). Ifthe TAT remaining time<TH_TAT, and the UE wants to keep the TAT running,the UE triggers the TAT status report.

The TH_TAT may be expressed in unit of ms, us, slot, symbol, etc. It mayalso be expressed by percentage of the TAT value, e.g. 20%, 30%, 50%,etc.

In the TAT status report, the UE includes the TAT status informationbased on the TH_TAT. An indicator, say TH indicator, is included toindicate whether the remaining time of the TAT is less than the TH_TATor larger than the TH_TAT.

The TAT status report may also include an indicator, say KR indicator,indicating whether the UE wants to keep the TAT running or not.

The KR indicator may not be included in the TAT status report MAC CE. Inthis case, the TH indicator can serve this purpose, i.e. the TAT statusreport including the TH indicator indicating that the remaining time ofthe TAT is less than the TH_TAT means that the UE wants to keep the TATrunning.

The TAT status report may also include the TAT status information ofother TATs than the TAT that triggered the TAT status report. The TATstatus report may include the TAT status information of all TATsconfigured in the UE.

The TAT status report may be transmitted by MAC CE or RRC message.

If it is transmitted by the MAC CE, an LCID value is allocated toindicate that this is the TAT status report MAC CE.

FIG. 13 shows an example of TAT status report for one TAG according tothe present disclosure.

In FIG. 13 , R represents Reserved bit, which is set to 0.

TAG ID represents a field indicating the TAG Identity of the TAG thattriggered the TAT status report. The length of the field is 2 bits.

Further, TH represents a field indicating whether the TAT remaining timeof the TAG corresponding to the TAG ID is less than the TH_TAT (setto 1) or larger than the TH_TAT (set to 0).

Finally, KR represents a field indicating whether the UE wants to keepthe TAT of the TAG corresponding to the TAG ID running (set to 1) or not(set to 0).

FIG. 14 shows an example of TAT status report for all TAGs according tothe present disclosure. Considering that there up to four TAGs can beconfigured, it is possible that the TAT status report MAC CE includesTAT status information for all TAGs, as shown in FIG. 14 .

The example in FIG. 14 can be further simplified by removing TAG ID. Itis shown in FIG. 15 . FIG. 15 shows another example of TAT status reportfor all TAGs according to the present disclosure.

When the network receives the TAT status report MAC CE from the UE, thenetwork identifies which TAT is about to expire based on the TH fieldand which TAT the UE wants to keep running based on the KR field.

If the network decides to keep a TAT running, the network transmitsTiming Advance Command (TAC) for the TAT to the UE. The TAC istransmitted by TAC MAC CE, Absolute TAC MAC CE, or RAR.

If the network decides to keep more than TATs running, the network maytransmit multiple TACs, each corresponding to each TAT.

FIG. 16 shows a procedure for transmitting a TAT status report accordingto the present disclosure. For convenience, in FIG. 16 , it is assumedthat the TAT status report MAC CE shown in FIG. 15 is used. However, itis not excluded a case of that the TAT status report MAC CE shown inFIG. 14 is used.

Referring to FIG. 16 , the UE receives TAG configuration informationincluding TAT and TH_TAT for each TAG. In this example, two TAGs, i.e.TAG1 (TAG ID=00) and TAG2 (TAG ID=01), are configured.

The UE receives TAC for TAG1, and starts TAT1. Similarly, the UEreceives TAC for TAG2, and starts TAT2.

Next, the network transmits another TAC for TAG1, but it is lost duringtransmission. The UE does not restart the TAT1 while the networkconsiders that the UE restarts the TAT1.

Later on, the remaining time of TAT1 becomes less than the TH_TAT1. TheUE wants to keep the TAT1 running, and triggers the TAT status report.

The UE transmits the TAT status report including TH indicator and KRindicator for each TAG. As TAG3 and TAG4 are not configured, the UE setsTH3, KR3, TH4, KR4 to 0. For TAG1, the UE sets TH1=1 to indicate thatthe remaining time of TAT1 is less than TH_TAT1, and also sets KR1=1 toindicate that the UE wants to keep the TAT1 running. For TAG2, the UEsets TH2=0 to indicate that the remaining time of TAT2 is larger thanTH_TAT2, but sets KR2=1 to indicate that the UE wants to keep the TAT2running.

The network receives a TAT status report from the UE, and identifiesthat TAT1 is about to expire but the UE wants to keep the TA1 running.Therefore, the network decides to transmit TAC for TAG1. However, thenetwork decides not to transmit TAC for TAG2 even if the UE indicatesthat the UE wants to keep the TAT2 running, because the remaining timeof TAT2 is larger than the TH_TAT2. Whether to transmit TAC for acertain TAG is up to network's own decision.

When the UE receives a TAC for TAG1, the UE restarts the TAT1.

According to the disclosure, the UE can inform the remaining time of TATand its preference to keep the TAT running. Based on the information,the network can transmit TAC to restart the TAT in the UE. Therefore,the UE can avoid release of UL resource due to TAT expiry when the UEwants to perform UL transmission in a near future. This would help toreduce the delay in UL transmission.

1. A method for transmitting a Time Alignment Timer (TAT) status reportby a user equipment (UE) in a wireless communication system, the methodcomprising: configuring one or more Timing Advance Groups (TAGs);receiving a Timing Advance Command (TAC) for one TAG of the one or moreTAGs; starting a TAT for the one TAG; triggering the TAT status reportwhen a remaining time of the TAT for the one TAG is less than athreshold for the one TAG; and transmitting the TAT status report to anetwork, wherein the TAT status report includes a first type indicationindicating that the remaining time of the TAT for the one TAG is lessthan the threshold.
 2. The method of claim 1, wherein, based on a numberof configured TAGs being greater than 2, the TAT status report furtherincludes first type indications indicating whether the remaining timesof the TATs for the one or more TAGs other than the one TAG is less thanthe threshold or not.
 3. The method of claim 1, wherein the TAT statusreport further includes second type indications for the one or more TAGsindicating whether the UE wants to keep the TAT running or not.
 4. Themethod of claim 1, further comprising receiving information about one ormore thresholds for the one or more TAGs from the network.
 5. The methodof claim 1, further comprising: receiving a TAC for the one TAG aftertransmitting the TAT status report; and restarting the TAT for the oneTAG.
 6. A user equipment (UE) in a wireless communication system, the UEcomprising: at least one transceiver; at least one processor; and atleast one computer memory operably connectable to the at least oneprocessor and storing instructions that, when executed, cause the atleast one processor to perform operations comprising: configuring one ormore Timing Advance Groups (TAGs); receiving a Timing Advance Command(TAC) for one of the one or more TAGs; starting a Time Alignment Timer(TAT) for the one TAG; triggering the TAT status report when a remainingtime of the TAT for the one TAG is less than a threshold for the oneTAG; and transmitting the TAT status report to a network, wherein theTAT status report includes a first type indication indicating that theremaining time of the TAT for the one TAG is less than the threshold. 7.The UE of claim 6, wherein, based on a number of configured TAGs beinggreater than 2, the TAT status report further includes first typeindications indicating whether the remaining time of the TAT for the oneor more TAGs other than the one TAG is less than the threshold or not.8. The UE of claim 6, wherein the TAT status report further includessecond type indications for the one or more TAGs indicating whether theUE wants to keep the TAT running or not.
 9. The UE of claim 6, whereinthe operations further comprise receiving information about one or morethresholds for the one or more TAGs from the network.
 10. The UE ofclaim 6, wherein the operations further comprise: receiving a TAC forthe one TAG after transmitting the TAT status report; and restarting theTAT for the one TAG.
 11. An apparatus for a user equipment (UE), theapparatus comprising: at least one processor; and at least one computermemory operably connectable to the at least one processor and storinginstructions that, when executed, cause the at least one processor toperform operations comprising: configuring one or more Timing AdvanceGroups (TAGs); receiving a Timing Advance Command (TAC) for one of theone or more TAGs; starting a Time Alignment Timer (TAT) for the one TAG;triggering the TAT status report when a remaining time of the TAT forthe one TAG is less than a threshold for the one TAG; and transmittingthe TAT status report to a network, wherein the TAT status reportincludes a first type indication indicating that the remaining time ofthe TAT for the one TAG is less than the threshold.
 12. A computerreadable storage medium storing at least one computer program comprisinginstructions that, when executed by at least one processor, cause the atleast one processor to perform operations for a user equipment (UE), theoperations comprising: configuring one or more Timing Advance Groups(TAGs); receiving a Timing Advance Command (TAC) for one of the one ormore TAGs; starting a Time Alignment Timer (TAT) for the one TAG;triggering the TAT status report when a remaining time of the TAT forthe one TAG is less than a threshold for the one TAG; and transmittingthe TAT status report to a network, wherein the TAT status reportincludes a first type indication indicating that the remaining time ofthe TAT for the one TAG is less than the threshold.